move to a single file
This commit is contained in:
Júlio César Batista
parent
0fad458858
commit
442f61331e
2 changed files with 198 additions and 207 deletions
198
lib/pptx/pptx.go
198
lib/pptx/pptx.go
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@ -1,3 +1,12 @@
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// pptx is a package to create slide presentations in pptx (Microsoft Power Point) format.
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// A `.pptx` file is just a bunch of zip compressed `.xml` files following the Office Open XML (OOXML) format.
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// To see its content, you can just `unzip <path/to/file>.pptx -d <folder>`.
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// With this package, it is possible to create a `Presentation` and add `Slide`s to it.
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// Then, when saving the presentation, it will generate the required `.xml` files, compress them and write to the disk.
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// Note that this isn't a full implementation of the OOXML format, but a wrapper around it.
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// There's a base template with common files to the presentation and then when saving, the package generate only the slides and relationships.
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// The base template and slide templates were generated using https://python-pptx.readthedocs.io/en/latest/
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// For more information about OOXML, check http://officeopenxml.com/index.php
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package pptx
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import (
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@ -5,10 +14,199 @@ import (
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"bytes"
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_ "embed"
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"fmt"
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"image/png"
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"os"
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"strings"
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"text/template"
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"time"
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)
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type Presentation struct {
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Title string
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Description string
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Subject string
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Creator string
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// D2Version can't have letters, only numbers (`[0-9]`) and `.`
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// Otherwise, it may fail to open in PowerPoint
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D2Version string
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Slides []*Slide
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}
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type Slide struct {
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BoardPath []string
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Image []byte
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ImageWidth int
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ImageHeight int
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ImageTop int
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ImageLeft int
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}
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func NewPresentation(title, description, subject, creator, d2Version string) *Presentation {
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return &Presentation{
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Title: title,
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Description: description,
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Subject: subject,
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Creator: creator,
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D2Version: d2Version,
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}
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}
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func (p *Presentation) AddSlide(pngContent []byte, boardPath []string) error {
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src, err := png.Decode(bytes.NewReader(pngContent))
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if err != nil {
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return fmt.Errorf("error decoding PNG image: %v", err)
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}
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var width, height int
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srcSize := src.Bounds().Size()
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srcWidth, srcHeight := float64(srcSize.X), float64(srcSize.Y)
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// compute the size and position to fit the slide
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// if the image is wider than taller and its aspect ratio is, at least, the same as the available image space aspect ratio
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// then, set the image width to the available space and compute the height
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// ┌──────────────────────────────────────────────────┐ ─┬─
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// │ HEADER │ │
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// ├──┬────────────────────────────────────────────┬──┤ │ ─┬─
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// │ │ │ │ │ │
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// │ │ │ │ SLIDE │
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// │ │ │ │ HEIGHT │
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// │ │ │ │ │ IMAGE
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// │ │ │ │ │ HEIGHT
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// │ │ │ │ │ │
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// │ │ │ │ │ │
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// │ │ │ │ │ │
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// │ │ │ │ │ │
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// └──┴────────────────────────────────────────────┴──┘ ─┴─ ─┴─
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// ├────────────────────SLIDE WIDTH───────────────────┤
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// ├─────────────────IMAGE WIDTH────────────────┤
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if srcWidth/srcHeight >= IMAGE_ASPECT_RATIO {
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// here, the image aspect ratio is, at least, equal to the slide aspect ratio
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// so, it makes sense to expand the image horizontally to use as much as space as possible
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width = SLIDE_WIDTH
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height = int(float64(width) * (srcHeight / srcWidth))
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// first, try to make the image as wide as the slide
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// but, if this results in a tall image, use only the
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// image adjusted width to avoid overlapping with the header
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if height > IMAGE_HEIGHT {
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width = IMAGE_WIDTH
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height = int(float64(width) * (srcHeight / srcWidth))
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}
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} else {
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// here, the aspect ratio could be 4x3, in which the image is still wider than taller,
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// but expanding horizontally would result in an overflow
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// so, we expand to make it fit the available vertical space
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height = IMAGE_HEIGHT
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width = int(float64(height) * (srcWidth / srcHeight))
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}
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top := (IMAGE_HEIGHT - height) / 2
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left := (SLIDE_WIDTH - width) / 2
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slide := &Slide{
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BoardPath: make([]string, len(boardPath)),
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Image: pngContent,
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ImageWidth: width,
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ImageHeight: height,
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ImageTop: top,
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ImageLeft: left,
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}
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// it must copy the board path to avoid slice reference issues
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copy(slide.BoardPath, boardPath)
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p.Slides = append(p.Slides, slide)
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return nil
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}
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func (p *Presentation) SaveTo(filePath string) error {
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f, err := os.Create(filePath)
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if err != nil {
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return err
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}
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defer f.Close()
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zipWriter := zip.NewWriter(f)
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defer zipWriter.Close()
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if err = copyPptxTemplateTo(zipWriter); err != nil {
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return err
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}
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var slideFileNames []string
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for i, slide := range p.Slides {
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imageID := fmt.Sprintf("slide%dImage", i+1)
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slideFileName := fmt.Sprintf("slide%d", i+1)
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slideFileNames = append(slideFileNames, slideFileName)
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imageWriter, err := zipWriter.Create(fmt.Sprintf("ppt/media/%s.png", imageID))
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if err != nil {
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return err
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}
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_, err = imageWriter.Write(slide.Image)
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if err != nil {
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return err
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}
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err = addFileFromTemplate(zipWriter, fmt.Sprintf("ppt/slides/_rels/%s.xml.rels", slideFileName), RELS_SLIDE_XML, RelsSlideXmlContent{
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FileName: imageID,
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RelationshipID: imageID,
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})
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if err != nil {
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return err
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}
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err = addFileFromTemplate(zipWriter, fmt.Sprintf("ppt/slides/%s.xml", slideFileName), SLIDE_XML, getSlideXmlContent(imageID, slide))
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if err != nil {
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return err
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}
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}
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err = addFileFromTemplate(zipWriter, "[Content_Types].xml", CONTENT_TYPES_XML, ContentTypesXmlContent{
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FileNames: slideFileNames,
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})
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if err != nil {
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return err
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}
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err = addFileFromTemplate(zipWriter, "ppt/_rels/presentation.xml.rels", RELS_PRESENTATION_XML, getRelsPresentationXmlContent(slideFileNames))
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if err != nil {
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return err
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}
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err = addFileFromTemplate(zipWriter, "ppt/presentation.xml", PRESENTATION_XML, getPresentationXmlContent(slideFileNames))
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if err != nil {
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return err
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}
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dateTime := time.Now().Format(time.RFC3339)
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err = addFileFromTemplate(zipWriter, "docProps/core.xml", CORE_XML, CoreXmlContent{
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Creator: p.Creator,
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Subject: p.Subject,
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Description: p.Description,
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LastModifiedBy: p.Creator,
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Title: p.Title,
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Created: dateTime,
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Modified: dateTime,
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})
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if err != nil {
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return err
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}
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titles := make([]string, 0, len(p.Slides))
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for _, slide := range p.Slides {
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titles = append(titles, strings.Join(slide.BoardPath, "/"))
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}
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err = addFileFromTemplate(zipWriter, "docProps/app.xml", APP_XML, AppXmlContent{
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SlideCount: len(p.Slides),
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TitlesOfPartsCount: len(p.Slides) + 3,
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D2Version: p.D2Version,
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Titles: titles,
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})
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if err != nil {
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return err
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}
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return nil
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}
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// Measurements in OOXML are made in English Metric Units (EMUs) where 1 inch = 914,400 EMUs
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// The intent is to have a measurement unit that doesn't require floating points when dealing with centimeters, inches, points (DPI).
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// Office Open XML (OOXML) http://officeopenxml.com/prPresentation.php
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@ -1,207 +0,0 @@
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// pptx is a package to create slide presentations in pptx (Microsoft Power Point) format.
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// A `.pptx` file is just a bunch of zip compressed `.xml` files following the Office Open XML (OOXML) format.
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// To see its content, you can just `unzip <path/to/file>.pptx -d <folder>`.
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// With this package, it is possible to create a `Presentation` and add `Slide`s to it.
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// Then, when saving the presentation, it will generate the required `.xml` files, compress them and write to the disk.
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// Note that this isn't a full implementation of the OOXML format, but a wrapper around it.
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// There's a base template with common files to the presentation and then when saving, the package generate only the slides and relationships.
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// The base template and slide templates were generated using https://python-pptx.readthedocs.io/en/latest/
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// For more information about OOXML, check http://officeopenxml.com/index.php
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package pptx
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import (
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"archive/zip"
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"bytes"
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_ "embed"
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"fmt"
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"image/png"
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"os"
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"strings"
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"time"
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)
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type Presentation struct {
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Title string
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Description string
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Subject string
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Creator string
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// D2Version can't have letters, only numbers (`[0-9]`) and `.`
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// Otherwise, it may fail to open in PowerPoint
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D2Version string
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Slides []*Slide
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}
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type Slide struct {
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BoardPath []string
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Image []byte
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ImageWidth int
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ImageHeight int
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ImageTop int
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ImageLeft int
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}
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func NewPresentation(title, description, subject, creator, d2Version string) *Presentation {
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return &Presentation{
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Title: title,
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Description: description,
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Subject: subject,
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Creator: creator,
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D2Version: d2Version,
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}
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}
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func (p *Presentation) AddSlide(pngContent []byte, boardPath []string) error {
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src, err := png.Decode(bytes.NewReader(pngContent))
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if err != nil {
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return fmt.Errorf("error decoding PNG image: %v", err)
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}
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var width, height int
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srcSize := src.Bounds().Size()
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srcWidth, srcHeight := float64(srcSize.X), float64(srcSize.Y)
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// compute the size and position to fit the slide
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// if the image is wider than taller and its aspect ratio is, at least, the same as the available image space aspect ratio
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// then, set the image width to the available space and compute the height
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// ┌──────────────────────────────────────────────────┐ ─┬─
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// │ HEADER │ │
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// ├──┬────────────────────────────────────────────┬──┤ │ ─┬─
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// │ │ │ │ │ │
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// │ │ │ │ SLIDE │
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// │ │ │ │ HEIGHT │
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// │ │ │ │ │ IMAGE
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// │ │ │ │ │ HEIGHT
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// │ │ │ │ │ │
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// │ │ │ │ │ │
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// │ │ │ │ │ │
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// │ │ │ │ │ │
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// └──┴────────────────────────────────────────────┴──┘ ─┴─ ─┴─
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// ├────────────────────SLIDE WIDTH───────────────────┤
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// ├─────────────────IMAGE WIDTH────────────────┤
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if srcWidth/srcHeight >= IMAGE_ASPECT_RATIO {
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// here, the image aspect ratio is, at least, equal to the slide aspect ratio
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// so, it makes sense to expand the image horizontally to use as much as space as possible
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width = SLIDE_WIDTH
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height = int(float64(width) * (srcHeight / srcWidth))
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// first, try to make the image as wide as the slide
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// but, if this results in a tall image, use only the
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// image adjusted width to avoid overlapping with the header
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if height > IMAGE_HEIGHT {
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width = IMAGE_WIDTH
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height = int(float64(width) * (srcHeight / srcWidth))
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}
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} else {
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// here, the aspect ratio could be 4x3, in which the image is still wider than taller,
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// but expanding horizontally would result in an overflow
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// so, we expand to make it fit the available vertical space
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height = IMAGE_HEIGHT
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width = int(float64(height) * (srcWidth / srcHeight))
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}
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top := (IMAGE_HEIGHT - height) / 2
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left := (SLIDE_WIDTH - width) / 2
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slide := &Slide{
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BoardPath: make([]string, len(boardPath)),
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Image: pngContent,
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ImageWidth: width,
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ImageHeight: height,
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ImageTop: top,
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ImageLeft: left,
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}
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// it must copy the board path to avoid slice reference issues
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copy(slide.BoardPath, boardPath)
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p.Slides = append(p.Slides, slide)
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return nil
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}
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func (p *Presentation) SaveTo(filePath string) error {
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f, err := os.Create(filePath)
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if err != nil {
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return err
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}
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defer f.Close()
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zipWriter := zip.NewWriter(f)
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defer zipWriter.Close()
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if err = copyPptxTemplateTo(zipWriter); err != nil {
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return err
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}
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var slideFileNames []string
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for i, slide := range p.Slides {
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imageID := fmt.Sprintf("slide%dImage", i+1)
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slideFileName := fmt.Sprintf("slide%d", i+1)
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slideFileNames = append(slideFileNames, slideFileName)
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imageWriter, err := zipWriter.Create(fmt.Sprintf("ppt/media/%s.png", imageID))
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if err != nil {
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return err
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}
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_, err = imageWriter.Write(slide.Image)
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if err != nil {
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return err
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}
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err = addFileFromTemplate(zipWriter, fmt.Sprintf("ppt/slides/_rels/%s.xml.rels", slideFileName), RELS_SLIDE_XML, RelsSlideXmlContent{
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FileName: imageID,
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RelationshipID: imageID,
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})
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if err != nil {
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return err
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}
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err = addFileFromTemplate(zipWriter, fmt.Sprintf("ppt/slides/%s.xml", slideFileName), SLIDE_XML, getSlideXmlContent(imageID, slide))
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if err != nil {
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return err
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}
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}
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err = addFileFromTemplate(zipWriter, "[Content_Types].xml", CONTENT_TYPES_XML, ContentTypesXmlContent{
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FileNames: slideFileNames,
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})
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if err != nil {
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return err
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}
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err = addFileFromTemplate(zipWriter, "ppt/_rels/presentation.xml.rels", RELS_PRESENTATION_XML, getRelsPresentationXmlContent(slideFileNames))
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if err != nil {
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return err
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}
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err = addFileFromTemplate(zipWriter, "ppt/presentation.xml", PRESENTATION_XML, getPresentationXmlContent(slideFileNames))
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if err != nil {
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return err
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}
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dateTime := time.Now().Format(time.RFC3339)
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err = addFileFromTemplate(zipWriter, "docProps/core.xml", CORE_XML, CoreXmlContent{
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Creator: p.Creator,
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Subject: p.Subject,
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Description: p.Description,
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LastModifiedBy: p.Creator,
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Title: p.Title,
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Created: dateTime,
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Modified: dateTime,
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})
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if err != nil {
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return err
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}
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titles := make([]string, 0, len(p.Slides))
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for _, slide := range p.Slides {
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titles = append(titles, strings.Join(slide.BoardPath, "/"))
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}
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err = addFileFromTemplate(zipWriter, "docProps/app.xml", APP_XML, AppXmlContent{
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SlideCount: len(p.Slides),
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TitlesOfPartsCount: len(p.Slides) + 3,
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D2Version: p.D2Version,
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Titles: titles,
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})
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if err != nil {
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return err
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}
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return nil
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}
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